Bombus occidentalis
In 3 days ~10% in a week ~20%
Bombus occidentalis, the western bumble bee, is one of around 30 bumble bee species present in the western United States and western Canada. A recent review of all of its close relatives worldwide appears to have confirmed its status as a separate species.
Western bumble bee workers have three main color variations. The first color variation is found from northern California, north to British Columbia, and east to southwest Saskatchewan and Montana. B. occidentalis in these areas have yellow hair on front part of thorax. They are also marked by black hair segments on the basal section of the fourth abdominal segments have black hair and whitish lower edge of the fourth and fifth abdominal segments. In addition, they also have sparse whitish hairs that may appear black on the sixth abdominal segment, and an entirely black head.
The second color variation is found along the central coast in California. It has yellow hair on the sides of the second abdominal segment and all of the third abdominal segment and a reddish-brown hair on fifth abdominal segment.
The third color variation is found from the Rocky Mountains to Alaska. It has yellow hair on the thorax behind the... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Grand Teton National Park | 🇺🇸 United States | |
| 2 | Glacier National Park | 🇺🇸 United States | |
| 3 | Great Bear Rainforest | 🇨🇦 Canada | |
| 4 | Yellowstone National Park | 🇺🇸 United States | |
| 5 | Olympic National Park | 🇺🇸 United States | |
| 6 | Rocky Mountain National Park | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report a Western Bumble Bee sighting in Denver on a given day, based on 21 verified sightings from GBIF citizen-science data. It is the 198th most-seen of the 461 insects we can rate there. Over three days the chance rises to about 10%, and over a week to about 20%, if each day is a fresh chance.
July and September
In those months about 10% of wildlife watchers report a Western Bumble Bee in Denver on a given day, against under 5% in August and October–June, the lowest months.
Between 11 am and 2 pm
Across all the parks we cover, that three-hour window holds the most Western Bumble Bee sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
2nd of 2
Of the 2 cities where we can rate Western Bumble Bee sightings, Denver ranks 2nd at under 5%. The best odds are in Calgary (Canada, about 10%).
Same genus: Bombus
The closest relatives of the Western Bumble Bee that you can see in Denver (genus Bombus, Bumble Bees) are Hunt's Bumble Bee (about 20%), Golden Northern Bumble Bee (about 20%) and Brown-Belted Bumble Bee (about 20%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Western Bumble Bee is recorded against all the insects logged in Denver (21 verified sightings), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
